The present invention relates to a heat exchanger.
Japanese Patent Application Publication No. 2011-7411 discloses a heat exchanger including a plurality of stacked core plates, oil flow passages each formed between adjacent two of the core plates, and coolant flow passages each formed between adjacent two of the core plates. The oil flow passages and the coolant flow passages are alternatingly formed.
In the heat exchanger of the above-described patent document, a fin plate is disposed in an oil flow passage. Each of the core plates constituting a coolant flow passage includes a plurality of protruding portions protruding toward the coolant flow passage. The fin plates and the protruding portions are provided for improving the heat exchanging efficiency between the oil and the coolant.